Dozens of drone sightings have been reported over New Jersey since 18 November, according to local authorities.
The drones were initially spotted near the Raritan river, a waterway which feeds into the Round Valley Reservoir – the largest in New Jersey, the Associated Press reported.
The sightings soon spread to other parts of the state, including New Jersey’s coast.
Some of the flights were spotted near Picatinny Arsenal – a sensitive military research facility – as well as near President-elect Donald Trump’s golf course in the town of Bedminster, New Jersey.
In nearby New York City, several drones were reported flying over the Bronx on 12 December, a police official told CBS News, the BBC’s US partner.
Officers who responded to the incident saw the drones flying overhead, but they disappeared soon afterwards.
Drones have also been reported in other parts of the state, according to New York State Police.
Police in Connecticut have also confirmed that “suspicious drone activity” has taken place in various parts of the state. A drone detection system has been deployed around the towns of Groton and New London.
In Maryland, former Republican Governor Larry Hogan claimed he saw what appeared to be “dozens” of drones over his residence in Davidsonville, about 25 miles (40km) from Washington DC.
“Like many who have observed these drones, I do not know if this increasing activity over our skies is a threat to public safety or national security,” he wrote on X. “But the public is growing increasingly concerned and frustrated with the complete lack of transparency and the dismissive attitude of the federal government.”
In late November, the United States Air Force also confirmed that unidentified drones were spotted over three US airbases in the UK: RAF Lakenheath and RAF Mildenhall in Suffolk and RAF Feltwell in Norfolk.
UK defence sources told the BBC that suspicion had fallen on a “state actor” being responsible for the incursions.
In October, the Wall Street Journal also reported that mysterious drones were seen for 17 days near US military facilities in Virginia.